Comments Period: March 12, 2016– April 11, 2016
SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a permit application to construct the Climax Molybdenum Mine McNulty Gulch project, which would result in impacts to approximately 16.48 acres of waters of the United States, including wetlands, in or adjacent to McNulty Gulch. This notice is to inform interested parties of the proposed activity and to solicit comments.
AUTHORITY: This application is being evaluated under Section 10 of the Rivers and Harbors Act of 1899 for structures or work in or affecting navigable waters of the United States and/or Section 404 of the Clean Water Act for the discharge of dredged or fill material in waters of the United States.
APPLICANT: Climax Molybdenum, Attn: Mr. Ray Lazuk, 11236 Highway 91, Climax, CO 80429
LOCATION: The approximately 380-acre project site is located entirely within the Climax Mine near Leadville, Latitude 39.389420°, Longitude -106.171874°, Climax, Summit County, Colorado, and can be seen on the CO-COPPER MOUNTAIN USGS Topographic Quadrangle.
PROJECT DESCRIPTION: The applicant is proposing to construct an expansion of an existing overburden storage facility (OSF) in McNulty Gulch at the Climax Molybdenum Company’s Climax Mine (Climax) located on Fremont Pass near Leadville, Colorado.
The Climax Mine is a large surface mine that produces a silvery metal known as molybdenum. The mine has been in operation since 1916 and employs over 380 people. The molybdenite ore body is located beneath Bartlett Mountain and occurs at varying depths over a relatively large area. It is necessary to remove rock on top of and around the deposit to recover the ore, and not all of the mineralized rock contains sufficient molybdenum to be economical to process. The material that needs to be removed and is not sent for processing is referred to as overburden.
A relatively large area is needed to store the overburden which must be removed to enable mining and processing of the ore. Based on the available information, the overall project purpose is to provide additional area for 200 million tons (MT), or 122 million cubic yards (MCY), of overburden storage at Climax to enable economic recovery and processing of molybdenite ore to meet world-wide demand for molybdenum.
The existing OSF is proposed to be expanded to provide the needed 200 MT (122 million cubic yards) of additional storage for future mining. Construction includes: clearing and grubbing the area for the OSF expansion, salvaging soil for future reclamation, and constructing sub-drains to collect and segregate surface water and shallow groundwater that comes in contact with overburden from non-contact water, and constructing diversions to divert surface water run-on from areas north and east of the OSF that will not be impacted. This surface water run-on is proposed to be routed to the East Interceptor Ditch and will be available to the upper Tenmile Creek watershed. All water which comes in contact with the proposed OSF expansion materials would be collected and treated within the mine water management and treatment system, in the same way water from the existing OSF is presently collected and treated. The mine water management and treatment system operates under a discharge permit issued by the State of Colorado.
The OSF is proposed to be expanded through the dumping of overburden in lifts up to 200 feet in height. The lifts will generally be setback 200 feet from the crest of the previous lift, resulting in an approximately 2.4:1 overall slope to meet stability requirements. The angle of repose of the lifts will be flattened for reclamation. Impacts to jurisdictional aquatic resources associated with the expansion would result in the permanent loss of 16.08 acres of wetlnads and 0.40 acre of intermittent and perennial channel and shallow pond. No fens would be impacted as a result of the proposed action.
Environmental Setting. The mine is located at the top of the Continental Divide, bordering the Colorado River Basin and the Arkansas River Basin, as well as Summit, Eagle and Lake Counties. The site is characterized by a mountainous setting with a prevalence of wetlands. There are approximately 40 acres of high altitude montane and slope jurisdictional wetlands, to include approximately 4 acres of fens, within the project area. Wetlands typically exist in most flat areas on Mine property and adjacent slope areas. In addition, there are approximately 12,000 linear feet of stream channel.
Water in the northern portion of McNulty Gulch, which is not affected by mine operations or the existing McNulty Gulch OSF, is currently conveyed to Clinton Reservoir by the East Interceptor Ditch (EID). Clinton Reservoir is located in the Clinton Creek watershed and discharges to a series of ditches and natural drainages to Tenmile Creek at the northern boundary of Climax property.
Wetlands and other waters of the U.S. were also identified in the vicinity of alternative OSF locations in the upper Arkansas River basin and upper Clinton Gulch. Fieldwork was completed and a large amount of wetlands, including fens and side-slope wetlands, were delineated in these other watersheds.
Alternatives. The applicant has provided information concerning project alternatives. At the time of submittal of this Section 404 application, the applicant has identified 8 potential alternatives, to include a No Action alternative. These are identified briefly below with aquatic resources listed:
1) Expansion of Existing OSF in McNulty Gulch (200 MT)
• 37.24 acres of wetlands (which includes 4.64 acres of impact to fens).
• 0.56 acre of intermittent and perennial channel (11,567 linear feet) and shallow pond.
2) Expansion of Existing OSF in McNulty Gulch – Wetland Avoidance (200 MT) - Proposed
• 16.08 acres of wetlands (which includes no impacts to fens).
• 0.40 acre of intermittent and perennial channel (8,723 linear feet) and shallow pond
3) Use of Upper Clinton Gulch for 200 MT
• 67.16 acres of wetlands (which includes 7.91 acres of impact to fen).
• 2.27 acre of intermittent and perennial channel (703 linear feet) and shallow pond.
4) Use of Upper Arkansas River for 200MT
• 85.53 acres of wetlands (which includes 3.43 acres of impact to fen).
• 0.10 acre (1,553 linear feet) of intermittent channel and perennial channel and shallow
5) Split 200 MT between McNulty Gulch and Upper Clinton Gulch
• 14.65 acres wetlands (no impact to fens).
• 0.38 acre intermittent and perennial channel (8,569 linear feet) and shallow pond.
6) Split 200 MT between McNulty Gulch and Upper Arkansas River
• 22.82 acres wetlands (which includes no impacts to fen).
• 0.45 acre intermittent and perennial channel (8,930 linear feet) and shallow pond.
7) Split 200 MT between McNulty Gulch, and Upper Clinton and Upper Arkansas River
• 22.28 acres wetlands (which includes no impacts to fens).
• 0.38 acre intermittent and perennial channel (7,348 linear feet) and shallow pond.
Additional information concerning project alternatives may be available from the applicant. Other alternatives may develop during the review process for this permit application. All reasonable project alternatives, in particular those which may be less damaging to the aquatic environment, will be considered.
Mitigation. The Corps requires that applicants consider and use all reasonable and practical measures to avoid and minimize impacts to aquatic resources. If the applicant is unable to avoid or minimize all impacts, the Corps may require compensatory mitigation. All of the proposed impacts will occur in McNulty Gulch which is located within the Tenmile Creek watershed in the upper Colorado River basin. At this time, the applicant’s preferred option for providing mitigation is the use of the ILF for restoration of wetlands at Camp Hale. Depending on when and how many advanced wetland credits are available, Climax believes it may be able to compensate for all unavoidable impacts from the OSF expansion project at one time. If advance credits from the ILF are not available or insufficient to provide the necessary mitigation for the OSF expansion, there are mitigation options on Climax property (permittee-responsible mitigation) that could be used.
In addition, a relatively large amount of wetlands, including fens, which are located on a relatively flat bench immediately to the east of the proposed OSF were avoided by the proposed project. A preliminary monitoring plan is included to ensure the proposed project does not result in secondary (indirect) impacts to wetlands up-gradient of the expanded OSF.
OTHER GOVERNMENTAL AUTHORIZATIONS: Water quality certification, as required under Section 401 of the Clean Water Act from the Colorado Department of Health and Environment is required for this project. The applicant has indicated they have applied for certification.
HISTORIC PROPERTIES: The Corps will initiate consultation with the State Historic Preservation Officer under Section 106 of the National Historic Preservation Act, as appropriate.
ENDANGERED SPECIES: The Corps will initiate consultation with the U.S. Fish and Wildlife Service and/or the National Marine Fisheries Service, pursuant to Section 7 of the Endangered Species Act, as appropriate.
EVALUATION FACTORS: The decision whether to issue a permit will be based on an evaluation of the probable impacts, including cumulative impacts, of the described activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefit, which reasonably may be expected to accrue from the described activity, must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the described activity will be considered, including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood hazards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, consideration of property ownership and, in general, the needs and welfare of the people. The activity's impact on the public interest will include application of the Section 404(b)(1) guidelines promulgated by the Administrator, Environmental Protection Agency (40 CFR Part 230).
The Corps is soliciting comments from the public, Federal, State, and local agencies and officials, Indian tribes, and other interested parties in order to consider and evaluate the impacts of this proposed activity. Any comments received will be considered by the Corps to determine whether to issue, modify, condition, or deny a permit for this proposal. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects, and other public interest factors listed above. Comments are used in the preparation of an Environmental Assessment and/or an Environmental Impact Statement pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the proposed activity.
SUBMITTING COMMENTS: Written comments, referencing Public Notice SPK-2013-00045 must be submitted to the office listed below on or before April 11, 2016.
Matthew Montgomery, Project Manager
US Army Corps of Engineers, Sacramento District
400 Rood Avenue, Room 224
Grand Junction, Colorado 81501
970.243.1199 Ext 17
The Corps is particularly interested in receiving comments related to the proposal's probable impacts on the affected aquatic environment and the secondary and cumulative effects. Anyone may request, in writing, that a public hearing be held to consider this application. Requests shall specifically state, with particularity, the reason(s) for holding a public hearing. If the Corps determines that the information received in response to this notice is inadequate for thorough evaluation, a public hearing may be warranted. If a public hearing is warranted, interested parties will be notified of the time, date, and location. Please note that all comment letters received are subject to release to the public through the Freedom of Information Act. If you have questions or need additional information please contact the applicant or the Corps' project manager Matthew Montgomery, 970-243-1199 Ext. 17, Matthew.R.Montgomery@usace.army.mil.
Attachments: 4 drawings